
i just spent a few hours out in the rain. i rate it as medium - steady, not light, but definitely not pounding either. it was nearly 70 degrees this morning, so i wore a gore tex hard shell with the armpit zips fully unzipped, a pair of running shorts, a t-shirt, and water sandals. 20 minutes in, i noted that while the jacket was keeping all the water out, the rain had stopped beading up on the fabric.
the beading up is important. gore tex, eVent, and other waterproof/breathable fabrics (a) benefit from frequent washing to keep the tiny pores clear so they can vent moisture and (b) don't work nearly as well if the outside of the fabric is wet - the water that collects on the outside also blocks vapor from coming through the pores. DWR, durable water repellant, is the treatment on the outside of your hard shell that helps water bead up and roll off, as opposed to saturating the fabric.
sometimes, you can rejuvenate DWR with a quick run through a warm (but not hot) clothes dryer. Some manufacturers even recommend using a warm iron to rejuvenate the factory-impregnated DWR. You can't go wrong by following the manufacturer's instructions. i would never put a warm or hot iron near a nylon shell jacket or pants because i would be too concerned about damaging the fabric, but Outdoor Research recommends using a warm iron or clothes dryer for its gore tex shells. i also don't put eVent garments in the clothes dryer because the manufacturers and the company that makes eVent seem to universally recommend drip-drying. (notably, though, most Gore Tex products and Gore favor running the garment in a warm dryer).
While i generally check this before a big trip, properly cleaning and treating hard shells isn't part of my regular routine. i'm not at all surprised that my jacket needs a good clean and re-treat, i'm sure i haven't done that in months. and i wear this particular jacket quite a bit. it's in the washer now, along with my favorite pair of rain pants, running in warm water with nikwax tech wash or Sport Wash - i buy whatever is less expensive or on sale. though neither of these generates much in the way of soapy suds, you can get Sport Wash for high efficiency clothes washes like the front-loader we have at home.
another consideration is how to re-apply DWR. there are several brands. i have tried three of them, and they all seem to work about the same if you follow the instructions carefully. gore and eVent don't distinguish, saying spray-on or wash-in are both fine, but some manufacturers express a preference for spraying on. (wash-in means that right after you clean your jacket, you dump an ounce or two of the DWR into the washer and run it again. spray -on speaks for itself, you take the wet garment out of the washer, shake off the extra water, hang it, and spray the exterior with a spray bottle). i have tried spray-on treatments a few times, and honestly, i miss spots. and it's messy. i use wash-in DWR, whether the manufacturers recommend it or not, because it seems to be the only way i can get uniform results.